Bashar al-Assad, the president of Syria, has joked that he deserved to win the Nobel Peace Prize after it was awarded to the international weapons watchdog currently destroying his regime's massive chemical arsenal.

The prize, which was given to the Organisation for the Prohibition of Chemical Weapons (OPCW) on Friday, "should have been mine," he said.

The remark, which the Lebanese newspaper Al-Akhbar quoted, was made "jokingly" during a recent meeting with visitors at the presidential palace, the newspaper said.

However, it might be viewed as inappropriate when uttered by a president whose civil war has already cost more than 115,000 lives. A chemical weapons attack in Damascus in August, widely blamed on the Syrian government, reportedly killed more than 1,200 people.

The OPCW and the United Nations have a team of 60 experts and support staff, based in Damascus, working to destroy the country's chemical stockpiles. The arsenal is reportedly the largest in the Middle East, and the OPCW hopes to destroy it all by 2014. It is the first time that the body has attempted such a project in a war zone.

Staff of international and local organisations increasingly have become targets for assassinations and kidnappings as the war drags towards its third year.

On Monday four of the seven aid workers from the International Committee of the Red Cross and the Syrian Red Crescent were released after having been seized in an ambush on a road in Syria's northern Idlib province the day before.

Ewan Watson, a Red Cross spokesperson confirmed that those who were freed were "safe and sound," but refused to comment on the nationality of the abductees or on who was responsible for the attack.

A Syrian media activist in the area where the group were taken, who asked not to be named, told The Telegraph that the al Qaeda-linked Islamic State of Iraq and the Levant was responsible for the kidnapping.

The north of Syria has become increasingly lawless, with hundreds of rebel groups fighting with each other, as well as with the remaining Syrian government presence, over scraps of terrain, money and weapons in the area.

On Monday a car bomb detonated in the town of Darkush, close to the Turkish border, killing at least 27 people including three children, activists said. The blast targeted the market area of the town.

John Kerry, the US Secretary of State, met with peace envoy Lakhdar Brahimi in London yesterday as part of a renewed push to bring warring factions to talks in Geneva. Sergei Lavrov, the Russian foreign minister, had earlier called on Washington to bring the Syrian opposition to the negotiations proposed for mid-November.

"We believe that it is urgent to set a date to convene the conference and work toward a new Syria," said Mr Kerry. "There has to be a transition government."

The call came a day after the Syrian National Council (SNC) – a key component of the National Coalition recognised by most Arab and Western governments – ruled out attending any Geneva peace talks and said it would leave the umbrella group if it participated.